Birdsong MysteryCommentator Brad Klein tells the story of a treetop mimic in New York City's Central Park. For several years, careful birdwatchers noticed that they heard the Black-Throated Green Warbler weeks before they saw it. This puzzled them -- until someone noticed that the Warbler's song was alternating with that of the White-Throated Sparrow.

Birdsong Mystery

Birdsong Mystery

Birdsong Mystery

Commentator Brad Klein tells the story of a treetop mimic in New York City's Central Park. For several years, careful birdwatchers noticed that they heard the Black-Throated Green Warbler weeks before they saw it. This puzzled them — until someone noticed that the Warbler's song was alternating with that of the White-Throated Sparrow.